1583 lines
52 KiB
C
1583 lines
52 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
|
|
|
|
/***
|
|
This file is part of systemd.
|
|
|
|
Copyright 2015 Lennart Poettering
|
|
|
|
systemd is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU Lesser General Public License as published by
|
|
the Free Software Foundation; either version 2.1 of the License, or
|
|
(at your option) any later version.
|
|
|
|
systemd is distributed in the hope that it will be useful, but
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
|
***/
|
|
|
|
#include <gcrypt.h>
|
|
|
|
#include "alloc-util.h"
|
|
#include "dns-domain.h"
|
|
#include "hexdecoct.h"
|
|
#include "resolved-dns-dnssec.h"
|
|
#include "resolved-dns-packet.h"
|
|
#include "string-table.h"
|
|
|
|
/* Open question:
|
|
*
|
|
* How does the DNSSEC canonical form of a hostname with a label
|
|
* containing a dot look like, the way DNS-SD does it?
|
|
*
|
|
* TODO:
|
|
*
|
|
* - wildcard zones compatibility (NSEC/NSEC3 wildcard check is missing)
|
|
* - multi-label zone compatibility
|
|
* - cname/dname compatibility
|
|
* - nxdomain on qname
|
|
* - workable hack for the .corp, .home, .box case
|
|
* - bus calls to override DNSEC setting per interface
|
|
*
|
|
* */
|
|
|
|
#define VERIFY_RRS_MAX 256
|
|
#define MAX_KEY_SIZE (32*1024)
|
|
|
|
/* Permit a maximum clock skew of 1h 10min. This should be enough to deal with DST confusion */
|
|
#define SKEW_MAX (1*USEC_PER_HOUR + 10*USEC_PER_MINUTE)
|
|
|
|
/* Maximum number of NSEC3 iterations we'll do. */
|
|
#define NSEC3_ITERATIONS_MAX 2048
|
|
|
|
/*
|
|
* The DNSSEC Chain of trust:
|
|
*
|
|
* Normal RRs are protected via RRSIG RRs in combination with DNSKEY RRs, all in the same zone
|
|
* DNSKEY RRs are either protected like normal RRs, or via a DS from a zone "higher" up the tree
|
|
* DS RRs are protected like normal RRs
|
|
*
|
|
* Example chain:
|
|
* Normal RR → RRSIG/DNSKEY+ → DS → RRSIG/DNSKEY+ → DS → ... → DS → RRSIG/DNSKEY+ → DS
|
|
*/
|
|
|
|
static void initialize_libgcrypt(void) {
|
|
const char *p;
|
|
|
|
if (gcry_control(GCRYCTL_INITIALIZATION_FINISHED_P))
|
|
return;
|
|
|
|
p = gcry_check_version("1.4.5");
|
|
assert(p);
|
|
|
|
gcry_control(GCRYCTL_DISABLE_SECMEM);
|
|
gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0);
|
|
}
|
|
|
|
uint16_t dnssec_keytag(DnsResourceRecord *dnskey, bool mask_revoke) {
|
|
const uint8_t *p;
|
|
uint32_t sum, f;
|
|
size_t i;
|
|
|
|
/* The algorithm from RFC 4034, Appendix B. */
|
|
|
|
assert(dnskey);
|
|
assert(dnskey->key->type == DNS_TYPE_DNSKEY);
|
|
|
|
f = (uint32_t) dnskey->dnskey.flags;
|
|
|
|
if (mask_revoke)
|
|
f &= ~DNSKEY_FLAG_REVOKE;
|
|
|
|
sum = f + ((((uint32_t) dnskey->dnskey.protocol) << 8) + (uint32_t) dnskey->dnskey.algorithm);
|
|
|
|
p = dnskey->dnskey.key;
|
|
|
|
for (i = 0; i < dnskey->dnskey.key_size; i++)
|
|
sum += (i & 1) == 0 ? (uint32_t) p[i] << 8 : (uint32_t) p[i];
|
|
|
|
sum += (sum >> 16) & UINT32_C(0xFFFF);
|
|
|
|
return sum & UINT32_C(0xFFFF);
|
|
}
|
|
|
|
static int rr_compare(const void *a, const void *b) {
|
|
DnsResourceRecord **x = (DnsResourceRecord**) a, **y = (DnsResourceRecord**) b;
|
|
size_t m;
|
|
int r;
|
|
|
|
/* Let's order the RRs according to RFC 4034, Section 6.3 */
|
|
|
|
assert(x);
|
|
assert(*x);
|
|
assert((*x)->wire_format);
|
|
assert(y);
|
|
assert(*y);
|
|
assert((*y)->wire_format);
|
|
|
|
m = MIN(DNS_RESOURCE_RECORD_RDATA_SIZE(*x), DNS_RESOURCE_RECORD_RDATA_SIZE(*y));
|
|
|
|
r = memcmp(DNS_RESOURCE_RECORD_RDATA(*x), DNS_RESOURCE_RECORD_RDATA(*y), m);
|
|
if (r != 0)
|
|
return r;
|
|
|
|
if (DNS_RESOURCE_RECORD_RDATA_SIZE(*x) < DNS_RESOURCE_RECORD_RDATA_SIZE(*y))
|
|
return -1;
|
|
else if (DNS_RESOURCE_RECORD_RDATA_SIZE(*x) > DNS_RESOURCE_RECORD_RDATA_SIZE(*y))
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int dnssec_rsa_verify_raw(
|
|
const char *hash_algorithm,
|
|
const void *signature, size_t signature_size,
|
|
const void *data, size_t data_size,
|
|
const void *exponent, size_t exponent_size,
|
|
const void *modulus, size_t modulus_size) {
|
|
|
|
gcry_sexp_t public_key_sexp = NULL, data_sexp = NULL, signature_sexp = NULL;
|
|
gcry_mpi_t n = NULL, e = NULL, s = NULL;
|
|
gcry_error_t ge;
|
|
int r;
|
|
|
|
assert(hash_algorithm);
|
|
|
|
ge = gcry_mpi_scan(&s, GCRYMPI_FMT_USG, signature, signature_size, NULL);
|
|
if (ge != 0) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_mpi_scan(&e, GCRYMPI_FMT_USG, exponent, exponent_size, NULL);
|
|
if (ge != 0) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_mpi_scan(&n, GCRYMPI_FMT_USG, modulus, modulus_size, NULL);
|
|
if (ge != 0) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_sexp_build(&signature_sexp,
|
|
NULL,
|
|
"(sig-val (rsa (s %m)))",
|
|
s);
|
|
|
|
if (ge != 0) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_sexp_build(&data_sexp,
|
|
NULL,
|
|
"(data (flags pkcs1) (hash %s %b))",
|
|
hash_algorithm,
|
|
(int) data_size,
|
|
data);
|
|
if (ge != 0) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_sexp_build(&public_key_sexp,
|
|
NULL,
|
|
"(public-key (rsa (n %m) (e %m)))",
|
|
n,
|
|
e);
|
|
if (ge != 0) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_pk_verify(signature_sexp, data_sexp, public_key_sexp);
|
|
if (gpg_err_code(ge) == GPG_ERR_BAD_SIGNATURE)
|
|
r = 0;
|
|
else if (ge != 0) {
|
|
log_debug("RSA signature check failed: %s", gpg_strerror(ge));
|
|
r = -EIO;
|
|
} else
|
|
r = 1;
|
|
|
|
finish:
|
|
if (e)
|
|
gcry_mpi_release(e);
|
|
if (n)
|
|
gcry_mpi_release(n);
|
|
if (s)
|
|
gcry_mpi_release(s);
|
|
|
|
if (public_key_sexp)
|
|
gcry_sexp_release(public_key_sexp);
|
|
if (signature_sexp)
|
|
gcry_sexp_release(signature_sexp);
|
|
if (data_sexp)
|
|
gcry_sexp_release(data_sexp);
|
|
|
|
return r;
|
|
}
|
|
|
|
static int dnssec_rsa_verify(
|
|
const char *hash_algorithm,
|
|
const void *hash, size_t hash_size,
|
|
DnsResourceRecord *rrsig,
|
|
DnsResourceRecord *dnskey) {
|
|
|
|
size_t exponent_size, modulus_size;
|
|
void *exponent, *modulus;
|
|
|
|
assert(hash_algorithm);
|
|
assert(hash);
|
|
assert(hash_size > 0);
|
|
assert(rrsig);
|
|
assert(dnskey);
|
|
|
|
if (*(uint8_t*) dnskey->dnskey.key == 0) {
|
|
/* exponent is > 255 bytes long */
|
|
|
|
exponent = (uint8_t*) dnskey->dnskey.key + 3;
|
|
exponent_size =
|
|
((size_t) (((uint8_t*) dnskey->dnskey.key)[1]) << 8) |
|
|
((size_t) ((uint8_t*) dnskey->dnskey.key)[2]);
|
|
|
|
if (exponent_size < 256)
|
|
return -EINVAL;
|
|
|
|
if (3 + exponent_size >= dnskey->dnskey.key_size)
|
|
return -EINVAL;
|
|
|
|
modulus = (uint8_t*) dnskey->dnskey.key + 3 + exponent_size;
|
|
modulus_size = dnskey->dnskey.key_size - 3 - exponent_size;
|
|
|
|
} else {
|
|
/* exponent is <= 255 bytes long */
|
|
|
|
exponent = (uint8_t*) dnskey->dnskey.key + 1;
|
|
exponent_size = (size_t) ((uint8_t*) dnskey->dnskey.key)[0];
|
|
|
|
if (exponent_size <= 0)
|
|
return -EINVAL;
|
|
|
|
if (1 + exponent_size >= dnskey->dnskey.key_size)
|
|
return -EINVAL;
|
|
|
|
modulus = (uint8_t*) dnskey->dnskey.key + 1 + exponent_size;
|
|
modulus_size = dnskey->dnskey.key_size - 1 - exponent_size;
|
|
}
|
|
|
|
return dnssec_rsa_verify_raw(
|
|
hash_algorithm,
|
|
rrsig->rrsig.signature, rrsig->rrsig.signature_size,
|
|
hash, hash_size,
|
|
exponent, exponent_size,
|
|
modulus, modulus_size);
|
|
}
|
|
|
|
static int dnssec_ecdsa_verify_raw(
|
|
const char *hash_algorithm,
|
|
const char *curve,
|
|
const void *signature_r, size_t signature_r_size,
|
|
const void *signature_s, size_t signature_s_size,
|
|
const void *data, size_t data_size,
|
|
const void *key, size_t key_size) {
|
|
|
|
gcry_sexp_t public_key_sexp = NULL, data_sexp = NULL, signature_sexp = NULL;
|
|
gcry_mpi_t q = NULL, r = NULL, s = NULL;
|
|
gcry_error_t ge;
|
|
int k;
|
|
|
|
assert(hash_algorithm);
|
|
|
|
ge = gcry_mpi_scan(&r, GCRYMPI_FMT_USG, signature_r, signature_r_size, NULL);
|
|
if (ge != 0) {
|
|
k = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_mpi_scan(&s, GCRYMPI_FMT_USG, signature_s, signature_s_size, NULL);
|
|
if (ge != 0) {
|
|
k = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_mpi_scan(&q, GCRYMPI_FMT_USG, key, key_size, NULL);
|
|
if (ge != 0) {
|
|
k = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_sexp_build(&signature_sexp,
|
|
NULL,
|
|
"(sig-val (ecdsa (r %m) (s %m)))",
|
|
r,
|
|
s);
|
|
if (ge != 0) {
|
|
k = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_sexp_build(&data_sexp,
|
|
NULL,
|
|
"(data (flags rfc6979) (hash %s %b))",
|
|
hash_algorithm,
|
|
(int) data_size,
|
|
data);
|
|
if (ge != 0) {
|
|
k = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_sexp_build(&public_key_sexp,
|
|
NULL,
|
|
"(public-key (ecc (curve %s) (q %m)))",
|
|
curve,
|
|
q);
|
|
if (ge != 0) {
|
|
k = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
ge = gcry_pk_verify(signature_sexp, data_sexp, public_key_sexp);
|
|
if (gpg_err_code(ge) == GPG_ERR_BAD_SIGNATURE)
|
|
k = 0;
|
|
else if (ge != 0) {
|
|
log_debug("ECDSA signature check failed: %s", gpg_strerror(ge));
|
|
k = -EIO;
|
|
} else
|
|
k = 1;
|
|
finish:
|
|
if (r)
|
|
gcry_mpi_release(r);
|
|
if (s)
|
|
gcry_mpi_release(s);
|
|
if (q)
|
|
gcry_mpi_release(q);
|
|
|
|
if (public_key_sexp)
|
|
gcry_sexp_release(public_key_sexp);
|
|
if (signature_sexp)
|
|
gcry_sexp_release(signature_sexp);
|
|
if (data_sexp)
|
|
gcry_sexp_release(data_sexp);
|
|
|
|
return k;
|
|
}
|
|
|
|
static int dnssec_ecdsa_verify(
|
|
const char *hash_algorithm,
|
|
int algorithm,
|
|
const void *hash, size_t hash_size,
|
|
DnsResourceRecord *rrsig,
|
|
DnsResourceRecord *dnskey) {
|
|
|
|
const char *curve;
|
|
size_t key_size;
|
|
uint8_t *q;
|
|
|
|
assert(hash);
|
|
assert(hash_size);
|
|
assert(rrsig);
|
|
assert(dnskey);
|
|
|
|
if (algorithm == DNSSEC_ALGORITHM_ECDSAP256SHA256) {
|
|
key_size = 32;
|
|
curve = "NIST P-256";
|
|
} else if (algorithm == DNSSEC_ALGORITHM_ECDSAP384SHA384) {
|
|
key_size = 48;
|
|
curve = "NIST P-384";
|
|
} else
|
|
return -EOPNOTSUPP;
|
|
|
|
if (dnskey->dnskey.key_size != key_size * 2)
|
|
return -EINVAL;
|
|
|
|
if (rrsig->rrsig.signature_size != key_size * 2)
|
|
return -EINVAL;
|
|
|
|
q = alloca(key_size*2 + 1);
|
|
q[0] = 0x04; /* Prepend 0x04 to indicate an uncompressed key */
|
|
memcpy(q+1, dnskey->dnskey.key, key_size*2);
|
|
|
|
return dnssec_ecdsa_verify_raw(
|
|
hash_algorithm,
|
|
curve,
|
|
rrsig->rrsig.signature, key_size,
|
|
(uint8_t*) rrsig->rrsig.signature + key_size, key_size,
|
|
hash, hash_size,
|
|
q, key_size*2+1);
|
|
}
|
|
|
|
static void md_add_uint8(gcry_md_hd_t md, uint8_t v) {
|
|
gcry_md_write(md, &v, sizeof(v));
|
|
}
|
|
|
|
static void md_add_uint16(gcry_md_hd_t md, uint16_t v) {
|
|
v = htobe16(v);
|
|
gcry_md_write(md, &v, sizeof(v));
|
|
}
|
|
|
|
static void md_add_uint32(gcry_md_hd_t md, uint32_t v) {
|
|
v = htobe32(v);
|
|
gcry_md_write(md, &v, sizeof(v));
|
|
}
|
|
|
|
static int dnssec_rrsig_expired(DnsResourceRecord *rrsig, usec_t realtime) {
|
|
usec_t expiration, inception, skew;
|
|
|
|
assert(rrsig);
|
|
assert(rrsig->key->type == DNS_TYPE_RRSIG);
|
|
|
|
if (realtime == USEC_INFINITY)
|
|
realtime = now(CLOCK_REALTIME);
|
|
|
|
expiration = rrsig->rrsig.expiration * USEC_PER_SEC;
|
|
inception = rrsig->rrsig.inception * USEC_PER_SEC;
|
|
|
|
if (inception > expiration)
|
|
return -EKEYREJECTED;
|
|
|
|
/* Permit a certain amount of clock skew of 10% of the valid
|
|
* time range. This takes inspiration from unbound's
|
|
* resolver. */
|
|
skew = (expiration - inception) / 10;
|
|
if (skew > SKEW_MAX)
|
|
skew = SKEW_MAX;
|
|
|
|
if (inception < skew)
|
|
inception = 0;
|
|
else
|
|
inception -= skew;
|
|
|
|
if (expiration + skew < expiration)
|
|
expiration = USEC_INFINITY;
|
|
else
|
|
expiration += skew;
|
|
|
|
return realtime < inception || realtime > expiration;
|
|
}
|
|
|
|
static int algorithm_to_gcrypt_md(uint8_t algorithm) {
|
|
|
|
/* Translates a DNSSEC signature algorithm into a gcrypt
|
|
* digest identifier.
|
|
*
|
|
* Note that we implement all algorithms listed as "Must
|
|
* implement" and "Recommended to Implement" in RFC6944. We
|
|
* don't implement any algorithms that are listed as
|
|
* "Optional" or "Must Not Implement". Specifically, we do not
|
|
* implement RSAMD5, DSASHA1, DH, DSA-NSEC3-SHA1, and
|
|
* GOST-ECC. */
|
|
|
|
switch (algorithm) {
|
|
|
|
case DNSSEC_ALGORITHM_RSASHA1:
|
|
case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1:
|
|
return GCRY_MD_SHA1;
|
|
|
|
case DNSSEC_ALGORITHM_RSASHA256:
|
|
case DNSSEC_ALGORITHM_ECDSAP256SHA256:
|
|
return GCRY_MD_SHA256;
|
|
|
|
case DNSSEC_ALGORITHM_ECDSAP384SHA384:
|
|
return GCRY_MD_SHA384;
|
|
|
|
case DNSSEC_ALGORITHM_RSASHA512:
|
|
return GCRY_MD_SHA512;
|
|
|
|
default:
|
|
return -EOPNOTSUPP;
|
|
}
|
|
}
|
|
|
|
int dnssec_verify_rrset(
|
|
DnsAnswer *a,
|
|
const DnsResourceKey *key,
|
|
DnsResourceRecord *rrsig,
|
|
DnsResourceRecord *dnskey,
|
|
usec_t realtime,
|
|
DnssecResult *result) {
|
|
|
|
uint8_t wire_format_name[DNS_WIRE_FOMAT_HOSTNAME_MAX];
|
|
size_t hash_size;
|
|
void *hash;
|
|
DnsResourceRecord **list, *rr;
|
|
gcry_md_hd_t md = NULL;
|
|
int r, md_algorithm;
|
|
size_t k, n = 0;
|
|
|
|
assert(key);
|
|
assert(rrsig);
|
|
assert(dnskey);
|
|
assert(result);
|
|
assert(rrsig->key->type == DNS_TYPE_RRSIG);
|
|
assert(dnskey->key->type == DNS_TYPE_DNSKEY);
|
|
|
|
/* Verifies the the RRSet matching the specified "key" in "a",
|
|
* using the signature "rrsig" and the key "dnskey". It's
|
|
* assumed the RRSIG and DNSKEY match. */
|
|
|
|
md_algorithm = algorithm_to_gcrypt_md(rrsig->rrsig.algorithm);
|
|
if (md_algorithm == -EOPNOTSUPP) {
|
|
*result = DNSSEC_UNSUPPORTED_ALGORITHM;
|
|
return 0;
|
|
}
|
|
if (md_algorithm < 0)
|
|
return md_algorithm;
|
|
|
|
r = dnssec_rrsig_expired(rrsig, realtime);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0) {
|
|
*result = DNSSEC_SIGNATURE_EXPIRED;
|
|
return 0;
|
|
}
|
|
|
|
/* Collect all relevant RRs in a single array, so that we can look at the RRset */
|
|
list = newa(DnsResourceRecord *, a->n_rrs);
|
|
|
|
DNS_ANSWER_FOREACH(rr, a) {
|
|
r = dns_resource_key_equal(key, rr->key);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
/* We need the wire format for ordering, and digest calculation */
|
|
r = dns_resource_record_to_wire_format(rr, true);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
list[n++] = rr;
|
|
|
|
if (n > VERIFY_RRS_MAX)
|
|
return -E2BIG;
|
|
}
|
|
|
|
if (n <= 0)
|
|
return -ENODATA;
|
|
|
|
/* Bring the RRs into canonical order */
|
|
qsort_safe(list, n, sizeof(DnsResourceRecord*), rr_compare);
|
|
|
|
/* OK, the RRs are now in canonical order. Let's calculate the digest */
|
|
initialize_libgcrypt();
|
|
|
|
hash_size = gcry_md_get_algo_dlen(md_algorithm);
|
|
assert(hash_size > 0);
|
|
|
|
gcry_md_open(&md, md_algorithm, 0);
|
|
if (!md)
|
|
return -EIO;
|
|
|
|
md_add_uint16(md, rrsig->rrsig.type_covered);
|
|
md_add_uint8(md, rrsig->rrsig.algorithm);
|
|
md_add_uint8(md, rrsig->rrsig.labels);
|
|
md_add_uint32(md, rrsig->rrsig.original_ttl);
|
|
md_add_uint32(md, rrsig->rrsig.expiration);
|
|
md_add_uint32(md, rrsig->rrsig.inception);
|
|
md_add_uint16(md, rrsig->rrsig.key_tag);
|
|
|
|
r = dns_name_to_wire_format(rrsig->rrsig.signer, wire_format_name, sizeof(wire_format_name), true);
|
|
if (r < 0)
|
|
goto finish;
|
|
gcry_md_write(md, wire_format_name, r);
|
|
|
|
for (k = 0; k < n; k++) {
|
|
const char *suffix;
|
|
size_t l;
|
|
rr = list[k];
|
|
|
|
r = dns_name_suffix(DNS_RESOURCE_KEY_NAME(rr->key), rrsig->rrsig.labels, &suffix);
|
|
if (r < 0)
|
|
goto finish;
|
|
if (r > 0) /* This is a wildcard! */
|
|
gcry_md_write(md, (uint8_t[]) { 1, '*'}, 2);
|
|
|
|
r = dns_name_to_wire_format(suffix, wire_format_name, sizeof(wire_format_name), true);
|
|
if (r < 0)
|
|
goto finish;
|
|
gcry_md_write(md, wire_format_name, r);
|
|
|
|
md_add_uint16(md, rr->key->type);
|
|
md_add_uint16(md, rr->key->class);
|
|
md_add_uint32(md, rrsig->rrsig.original_ttl);
|
|
|
|
l = DNS_RESOURCE_RECORD_RDATA_SIZE(rr);
|
|
assert(l <= 0xFFFF);
|
|
|
|
md_add_uint16(md, (uint16_t) l);
|
|
gcry_md_write(md, DNS_RESOURCE_RECORD_RDATA(rr), l);
|
|
}
|
|
|
|
hash = gcry_md_read(md, 0);
|
|
if (!hash) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
switch (rrsig->rrsig.algorithm) {
|
|
|
|
case DNSSEC_ALGORITHM_RSASHA1:
|
|
case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1:
|
|
case DNSSEC_ALGORITHM_RSASHA256:
|
|
case DNSSEC_ALGORITHM_RSASHA512:
|
|
r = dnssec_rsa_verify(
|
|
gcry_md_algo_name(md_algorithm),
|
|
hash, hash_size,
|
|
rrsig,
|
|
dnskey);
|
|
break;
|
|
|
|
case DNSSEC_ALGORITHM_ECDSAP256SHA256:
|
|
case DNSSEC_ALGORITHM_ECDSAP384SHA384:
|
|
r = dnssec_ecdsa_verify(
|
|
gcry_md_algo_name(md_algorithm),
|
|
rrsig->rrsig.algorithm,
|
|
hash, hash_size,
|
|
rrsig,
|
|
dnskey);
|
|
break;
|
|
}
|
|
|
|
if (r < 0)
|
|
goto finish;
|
|
|
|
*result = r ? DNSSEC_VALIDATED : DNSSEC_INVALID;
|
|
r = 0;
|
|
|
|
finish:
|
|
gcry_md_close(md);
|
|
return r;
|
|
}
|
|
|
|
int dnssec_rrsig_match_dnskey(DnsResourceRecord *rrsig, DnsResourceRecord *dnskey, bool revoked_ok) {
|
|
|
|
assert(rrsig);
|
|
assert(dnskey);
|
|
|
|
/* Checks if the specified DNSKEY RR matches the key used for
|
|
* the signature in the specified RRSIG RR */
|
|
|
|
if (rrsig->key->type != DNS_TYPE_RRSIG)
|
|
return -EINVAL;
|
|
|
|
if (dnskey->key->type != DNS_TYPE_DNSKEY)
|
|
return 0;
|
|
if (dnskey->key->class != rrsig->key->class)
|
|
return 0;
|
|
if ((dnskey->dnskey.flags & DNSKEY_FLAG_ZONE_KEY) == 0)
|
|
return 0;
|
|
if (!revoked_ok && (dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE))
|
|
return 0;
|
|
if (dnskey->dnskey.protocol != 3)
|
|
return 0;
|
|
if (dnskey->dnskey.algorithm != rrsig->rrsig.algorithm)
|
|
return 0;
|
|
|
|
if (dnssec_keytag(dnskey, false) != rrsig->rrsig.key_tag)
|
|
return 0;
|
|
|
|
return dns_name_equal(DNS_RESOURCE_KEY_NAME(dnskey->key), rrsig->rrsig.signer);
|
|
}
|
|
|
|
int dnssec_key_match_rrsig(const DnsResourceKey *key, DnsResourceRecord *rrsig) {
|
|
int r;
|
|
|
|
assert(key);
|
|
assert(rrsig);
|
|
|
|
/* Checks if the specified RRSIG RR protects the RRSet of the specified RR key. */
|
|
|
|
if (rrsig->key->type != DNS_TYPE_RRSIG)
|
|
return 0;
|
|
if (rrsig->key->class != key->class)
|
|
return 0;
|
|
if (rrsig->rrsig.type_covered != key->type)
|
|
return 0;
|
|
|
|
/* Make sure signer is a parent of the RRset */
|
|
r = dns_name_endswith(DNS_RESOURCE_KEY_NAME(rrsig->key), rrsig->rrsig.signer);
|
|
if (r <= 0)
|
|
return r;
|
|
|
|
/* Make sure the owner name has at least as many labels as the "label" fields indicates. */
|
|
r = dns_name_count_labels(DNS_RESOURCE_KEY_NAME(rrsig->key));
|
|
if (r < 0)
|
|
return r;
|
|
if (r < rrsig->rrsig.labels)
|
|
return 0;
|
|
|
|
return dns_name_equal(DNS_RESOURCE_KEY_NAME(rrsig->key), DNS_RESOURCE_KEY_NAME(key));
|
|
}
|
|
|
|
static int dnssec_fix_rrset_ttl(DnsAnswer *a, const DnsResourceKey *key, DnsResourceRecord *rrsig, usec_t realtime) {
|
|
DnsResourceRecord *rr;
|
|
int r;
|
|
|
|
assert(key);
|
|
assert(rrsig);
|
|
|
|
DNS_ANSWER_FOREACH(rr, a) {
|
|
r = dns_resource_key_equal(key, rr->key);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
/* Pick the TTL as the minimum of the RR's TTL, the
|
|
* RR's original TTL according to the RRSIG and the
|
|
* RRSIG's own TTL, see RFC 4035, Section 5.3.3 */
|
|
rr->ttl = MIN3(rr->ttl, rrsig->rrsig.original_ttl, rrsig->ttl);
|
|
rr->expiry = rrsig->rrsig.expiration * USEC_PER_SEC;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dnssec_verify_rrset_search(
|
|
DnsAnswer *a,
|
|
const DnsResourceKey *key,
|
|
DnsAnswer *validated_dnskeys,
|
|
usec_t realtime,
|
|
DnssecResult *result) {
|
|
|
|
bool found_rrsig = false, found_invalid = false, found_expired_rrsig = false, found_unsupported_algorithm = false;
|
|
DnsResourceRecord *rrsig;
|
|
int r;
|
|
|
|
assert(key);
|
|
assert(result);
|
|
|
|
/* Verifies all RRs from "a" that match the key "key" against DNSKEYs in "validated_dnskeys" */
|
|
|
|
if (!a || a->n_rrs <= 0)
|
|
return -ENODATA;
|
|
|
|
/* Iterate through each RRSIG RR. */
|
|
DNS_ANSWER_FOREACH(rrsig, a) {
|
|
DnsResourceRecord *dnskey;
|
|
DnsAnswerFlags flags;
|
|
|
|
/* Is this an RRSIG RR that applies to RRs matching our key? */
|
|
r = dnssec_key_match_rrsig(key, rrsig);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
found_rrsig = true;
|
|
|
|
/* Look for a matching key */
|
|
DNS_ANSWER_FOREACH_FLAGS(dnskey, flags, validated_dnskeys) {
|
|
DnssecResult one_result;
|
|
|
|
if ((flags & DNS_ANSWER_AUTHENTICATED) == 0)
|
|
continue;
|
|
|
|
/* Is this a DNSKEY RR that matches they key of our RRSIG? */
|
|
r = dnssec_rrsig_match_dnskey(rrsig, dnskey, false);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
/* Take the time here, if it isn't set yet, so
|
|
* that we do all validations with the same
|
|
* time. */
|
|
if (realtime == USEC_INFINITY)
|
|
realtime = now(CLOCK_REALTIME);
|
|
|
|
/* Yay, we found a matching RRSIG with a matching
|
|
* DNSKEY, awesome. Now let's verify all entries of
|
|
* the RRSet against the RRSIG and DNSKEY
|
|
* combination. */
|
|
|
|
r = dnssec_verify_rrset(a, key, rrsig, dnskey, realtime, &one_result);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
switch (one_result) {
|
|
|
|
case DNSSEC_VALIDATED:
|
|
/* Yay, the RR has been validated,
|
|
* return immediately, but fix up the expiry */
|
|
r = dnssec_fix_rrset_ttl(a, key, rrsig, realtime);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
*result = DNSSEC_VALIDATED;
|
|
return 0;
|
|
|
|
case DNSSEC_INVALID:
|
|
/* If the signature is invalid, let's try another
|
|
key and/or signature. After all they
|
|
key_tags and stuff are not unique, and
|
|
might be shared by multiple keys. */
|
|
found_invalid = true;
|
|
continue;
|
|
|
|
case DNSSEC_UNSUPPORTED_ALGORITHM:
|
|
/* If the key algorithm is
|
|
unsupported, try another
|
|
RRSIG/DNSKEY pair, but remember we
|
|
encountered this, so that we can
|
|
return a proper error when we
|
|
encounter nothing better. */
|
|
found_unsupported_algorithm = true;
|
|
continue;
|
|
|
|
case DNSSEC_SIGNATURE_EXPIRED:
|
|
/* If the signature is expired, try
|
|
another one, but remember it, so
|
|
that we can return this */
|
|
found_expired_rrsig = true;
|
|
continue;
|
|
|
|
default:
|
|
assert_not_reached("Unexpected DNSSEC validation result");
|
|
}
|
|
}
|
|
}
|
|
|
|
if (found_expired_rrsig)
|
|
*result = DNSSEC_SIGNATURE_EXPIRED;
|
|
else if (found_unsupported_algorithm)
|
|
*result = DNSSEC_UNSUPPORTED_ALGORITHM;
|
|
else if (found_invalid)
|
|
*result = DNSSEC_INVALID;
|
|
else if (found_rrsig)
|
|
*result = DNSSEC_MISSING_KEY;
|
|
else
|
|
*result = DNSSEC_NO_SIGNATURE;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dnssec_has_rrsig(DnsAnswer *a, const DnsResourceKey *key) {
|
|
DnsResourceRecord *rr;
|
|
int r;
|
|
|
|
/* Checks whether there's at least one RRSIG in 'a' that proctects RRs of the specified key */
|
|
|
|
DNS_ANSWER_FOREACH(rr, a) {
|
|
r = dnssec_key_match_rrsig(key, rr);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0)
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dnssec_canonicalize(const char *n, char *buffer, size_t buffer_max) {
|
|
size_t c = 0;
|
|
int r;
|
|
|
|
/* Converts the specified hostname into DNSSEC canonicalized
|
|
* form. */
|
|
|
|
if (buffer_max < 2)
|
|
return -ENOBUFS;
|
|
|
|
for (;;) {
|
|
size_t i;
|
|
|
|
r = dns_label_unescape(&n, buffer, buffer_max);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
break;
|
|
if (r > 0) {
|
|
int k;
|
|
|
|
/* DNSSEC validation is always done on the ASCII version of the label */
|
|
k = dns_label_apply_idna(buffer, r, buffer, buffer_max);
|
|
if (k < 0)
|
|
return k;
|
|
if (k > 0)
|
|
r = k;
|
|
}
|
|
|
|
if (buffer_max < (size_t) r + 2)
|
|
return -ENOBUFS;
|
|
|
|
/* The DNSSEC canonical form is not clear on what to
|
|
* do with dots appearing in labels, the way DNS-SD
|
|
* does it. Refuse it for now. */
|
|
|
|
if (memchr(buffer, '.', r))
|
|
return -EINVAL;
|
|
|
|
for (i = 0; i < (size_t) r; i ++) {
|
|
if (buffer[i] >= 'A' && buffer[i] <= 'Z')
|
|
buffer[i] = buffer[i] - 'A' + 'a';
|
|
}
|
|
|
|
buffer[r] = '.';
|
|
|
|
buffer += r + 1;
|
|
c += r + 1;
|
|
|
|
buffer_max -= r + 1;
|
|
}
|
|
|
|
if (c <= 0) {
|
|
/* Not even a single label: this is the root domain name */
|
|
|
|
assert(buffer_max > 2);
|
|
buffer[0] = '.';
|
|
buffer[1] = 0;
|
|
|
|
return 1;
|
|
}
|
|
|
|
return (int) c;
|
|
}
|
|
|
|
static int digest_to_gcrypt_md(uint8_t algorithm) {
|
|
|
|
/* Translates a DNSSEC digest algorithm into a gcrypt digest identifier */
|
|
|
|
switch (algorithm) {
|
|
|
|
case DNSSEC_DIGEST_SHA1:
|
|
return GCRY_MD_SHA1;
|
|
|
|
case DNSSEC_DIGEST_SHA256:
|
|
return GCRY_MD_SHA256;
|
|
|
|
case DNSSEC_DIGEST_SHA384:
|
|
return GCRY_MD_SHA384;
|
|
|
|
default:
|
|
return -EOPNOTSUPP;
|
|
}
|
|
}
|
|
|
|
int dnssec_verify_dnskey(DnsResourceRecord *dnskey, DnsResourceRecord *ds, bool mask_revoke) {
|
|
char owner_name[DNSSEC_CANONICAL_HOSTNAME_MAX];
|
|
gcry_md_hd_t md = NULL;
|
|
size_t hash_size;
|
|
int md_algorithm, r;
|
|
void *result;
|
|
|
|
assert(dnskey);
|
|
assert(ds);
|
|
|
|
/* Implements DNSKEY verification by a DS, according to RFC 4035, section 5.2 */
|
|
|
|
if (dnskey->key->type != DNS_TYPE_DNSKEY)
|
|
return -EINVAL;
|
|
if (ds->key->type != DNS_TYPE_DS)
|
|
return -EINVAL;
|
|
if ((dnskey->dnskey.flags & DNSKEY_FLAG_ZONE_KEY) == 0)
|
|
return -EKEYREJECTED;
|
|
if (!mask_revoke && (dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE))
|
|
return -EKEYREJECTED;
|
|
if (dnskey->dnskey.protocol != 3)
|
|
return -EKEYREJECTED;
|
|
|
|
if (dnskey->dnskey.algorithm != ds->ds.algorithm)
|
|
return 0;
|
|
if (dnssec_keytag(dnskey, mask_revoke) != ds->ds.key_tag)
|
|
return 0;
|
|
|
|
initialize_libgcrypt();
|
|
|
|
md_algorithm = digest_to_gcrypt_md(ds->ds.digest_type);
|
|
if (md_algorithm < 0)
|
|
return md_algorithm;
|
|
|
|
hash_size = gcry_md_get_algo_dlen(md_algorithm);
|
|
assert(hash_size > 0);
|
|
|
|
if (ds->ds.digest_size != hash_size)
|
|
return 0;
|
|
|
|
r = dnssec_canonicalize(DNS_RESOURCE_KEY_NAME(dnskey->key), owner_name, sizeof(owner_name));
|
|
if (r < 0)
|
|
return r;
|
|
|
|
gcry_md_open(&md, md_algorithm, 0);
|
|
if (!md)
|
|
return -EIO;
|
|
|
|
gcry_md_write(md, owner_name, r);
|
|
if (mask_revoke)
|
|
md_add_uint16(md, dnskey->dnskey.flags & ~DNSKEY_FLAG_REVOKE);
|
|
else
|
|
md_add_uint16(md, dnskey->dnskey.flags);
|
|
md_add_uint8(md, dnskey->dnskey.protocol);
|
|
md_add_uint8(md, dnskey->dnskey.algorithm);
|
|
gcry_md_write(md, dnskey->dnskey.key, dnskey->dnskey.key_size);
|
|
|
|
result = gcry_md_read(md, 0);
|
|
if (!result) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
r = memcmp(result, ds->ds.digest, ds->ds.digest_size) != 0;
|
|
|
|
finish:
|
|
gcry_md_close(md);
|
|
return r;
|
|
}
|
|
|
|
int dnssec_verify_dnskey_search(DnsResourceRecord *dnskey, DnsAnswer *validated_ds) {
|
|
DnsResourceRecord *ds;
|
|
DnsAnswerFlags flags;
|
|
int r;
|
|
|
|
assert(dnskey);
|
|
|
|
if (dnskey->key->type != DNS_TYPE_DNSKEY)
|
|
return 0;
|
|
|
|
DNS_ANSWER_FOREACH_FLAGS(ds, flags, validated_ds) {
|
|
|
|
if ((flags & DNS_ANSWER_AUTHENTICATED) == 0)
|
|
continue;
|
|
|
|
if (ds->key->type != DNS_TYPE_DS)
|
|
continue;
|
|
|
|
if (ds->key->class != dnskey->key->class)
|
|
continue;
|
|
|
|
r = dns_name_equal(DNS_RESOURCE_KEY_NAME(dnskey->key), DNS_RESOURCE_KEY_NAME(ds->key));
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
r = dnssec_verify_dnskey(dnskey, ds, false);
|
|
if (r == -EKEYREJECTED)
|
|
return 0; /* The DNSKEY is revoked or otherwise invalid, we won't bless it */
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0)
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int nsec3_hash_to_gcrypt_md(uint8_t algorithm) {
|
|
|
|
/* Translates a DNSSEC NSEC3 hash algorithm into a gcrypt digest identifier */
|
|
|
|
switch (algorithm) {
|
|
|
|
case NSEC3_ALGORITHM_SHA1:
|
|
return GCRY_MD_SHA1;
|
|
|
|
default:
|
|
return -EOPNOTSUPP;
|
|
}
|
|
}
|
|
|
|
int dnssec_nsec3_hash(DnsResourceRecord *nsec3, const char *name, void *ret) {
|
|
uint8_t wire_format[DNS_WIRE_FOMAT_HOSTNAME_MAX];
|
|
gcry_md_hd_t md = NULL;
|
|
size_t hash_size;
|
|
int algorithm;
|
|
void *result;
|
|
unsigned k;
|
|
int r;
|
|
|
|
assert(nsec3);
|
|
assert(name);
|
|
assert(ret);
|
|
|
|
if (nsec3->key->type != DNS_TYPE_NSEC3)
|
|
return -EINVAL;
|
|
|
|
if (nsec3->nsec3.iterations > NSEC3_ITERATIONS_MAX) {
|
|
log_debug("Ignoring NSEC3 RR %s with excessive number of iterations.", dns_resource_record_to_string(nsec3));
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
algorithm = nsec3_hash_to_gcrypt_md(nsec3->nsec3.algorithm);
|
|
if (algorithm < 0)
|
|
return algorithm;
|
|
|
|
initialize_libgcrypt();
|
|
|
|
hash_size = gcry_md_get_algo_dlen(algorithm);
|
|
assert(hash_size > 0);
|
|
|
|
if (nsec3->nsec3.next_hashed_name_size != hash_size)
|
|
return -EINVAL;
|
|
|
|
r = dns_name_to_wire_format(name, wire_format, sizeof(wire_format), true);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
gcry_md_open(&md, algorithm, 0);
|
|
if (!md)
|
|
return -EIO;
|
|
|
|
gcry_md_write(md, wire_format, r);
|
|
gcry_md_write(md, nsec3->nsec3.salt, nsec3->nsec3.salt_size);
|
|
|
|
result = gcry_md_read(md, 0);
|
|
if (!result) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
|
|
for (k = 0; k < nsec3->nsec3.iterations; k++) {
|
|
uint8_t tmp[hash_size];
|
|
memcpy(tmp, result, hash_size);
|
|
|
|
gcry_md_reset(md);
|
|
gcry_md_write(md, tmp, hash_size);
|
|
gcry_md_write(md, nsec3->nsec3.salt, nsec3->nsec3.salt_size);
|
|
|
|
result = gcry_md_read(md, 0);
|
|
if (!result) {
|
|
r = -EIO;
|
|
goto finish;
|
|
}
|
|
}
|
|
|
|
memcpy(ret, result, hash_size);
|
|
r = (int) hash_size;
|
|
|
|
finish:
|
|
gcry_md_close(md);
|
|
return r;
|
|
}
|
|
|
|
static int nsec3_is_good(DnsResourceRecord *rr, DnsAnswerFlags flags, DnsResourceRecord *nsec3) {
|
|
const char *a, *b;
|
|
int r;
|
|
|
|
assert(rr);
|
|
|
|
if (rr->key->type != DNS_TYPE_NSEC3)
|
|
return 0;
|
|
|
|
/* RFC 5155, Section 8.2 says we MUST ignore NSEC3 RRs with flags != 0 or 1 */
|
|
if (!IN_SET(rr->nsec3.flags, 0, 1))
|
|
return 0;
|
|
|
|
/* Ignore NSEC3 RRs whose algorithm we don't know */
|
|
if (nsec3_hash_to_gcrypt_md(rr->nsec3.algorithm) < 0)
|
|
return 0;
|
|
/* Ignore NSEC3 RRs with an excessive number of required iterations */
|
|
if (rr->nsec3.iterations > NSEC3_ITERATIONS_MAX)
|
|
return 0;
|
|
|
|
if (!nsec3)
|
|
return 1;
|
|
|
|
/* If a second NSEC3 RR is specified, also check if they are from the same zone. */
|
|
|
|
if (nsec3 == rr) /* Shortcut */
|
|
return 1;
|
|
|
|
if (rr->key->class != nsec3->key->class)
|
|
return 0;
|
|
if (rr->nsec3.algorithm != nsec3->nsec3.algorithm)
|
|
return 0;
|
|
if (rr->nsec3.iterations != nsec3->nsec3.iterations)
|
|
return 0;
|
|
if (rr->nsec3.salt_size != nsec3->nsec3.salt_size)
|
|
return 0;
|
|
if (memcmp(rr->nsec3.salt, nsec3->nsec3.salt, rr->nsec3.salt_size) != 0)
|
|
return 0;
|
|
|
|
a = DNS_RESOURCE_KEY_NAME(rr->key);
|
|
r = dns_name_parent(&a); /* strip off hash */
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
return 0;
|
|
|
|
b = DNS_RESOURCE_KEY_NAME(nsec3->key);
|
|
r = dns_name_parent(&b); /* strip off hash */
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
return 0;
|
|
|
|
return dns_name_equal(a, b);
|
|
}
|
|
|
|
static int nsec3_hashed_domain(DnsResourceRecord *nsec3, const char *domain, const char *zone, char **ret) {
|
|
_cleanup_free_ char *l = NULL, *hashed_domain = NULL;
|
|
uint8_t hashed[DNSSEC_HASH_SIZE_MAX];
|
|
int hashed_size;
|
|
|
|
assert(nsec3);
|
|
assert(domain);
|
|
assert(zone);
|
|
assert(ret);
|
|
|
|
hashed_size = dnssec_nsec3_hash(nsec3, domain, hashed);
|
|
if (hashed_size < 0)
|
|
return hashed_size;
|
|
|
|
l = base32hexmem(hashed, hashed_size, false);
|
|
if (!l)
|
|
return -ENOMEM;
|
|
|
|
hashed_domain = strjoin(l, ".", zone, NULL);
|
|
if (!hashed_domain)
|
|
return -ENOMEM;
|
|
|
|
*ret = hashed_domain;
|
|
hashed_domain = NULL;
|
|
|
|
return hashed_size;
|
|
}
|
|
|
|
/* See RFC 5155, Section 8
|
|
* First try to find a NSEC3 record that matches our query precisely, if that fails, find the closest
|
|
* enclosure. Secondly, find a proof that there is no closer enclosure and either a proof that there
|
|
* is no wildcard domain as a direct descendant of the closest enclosure, or find an NSEC3 record that
|
|
* matches the wildcard domain.
|
|
*
|
|
* Based on this we can prove either the existence of the record in @key, or NXDOMAIN or NODATA, or
|
|
* that there is no proof either way. The latter is the case if a the proof of non-existence of a given
|
|
* name uses an NSEC3 record with the opt-out bit set. Lastly, if we are given insufficient NSEC3 records
|
|
* to conclude anything we indicate this by returning NO_RR. */
|
|
static int dnssec_test_nsec3(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl) {
|
|
_cleanup_free_ char *next_closer_domain = NULL, *wildcard = NULL, *wildcard_domain = NULL;
|
|
const char *zone, *p, *pp = NULL;
|
|
DnsResourceRecord *rr, *enclosure_rr, *suffix_rr, *wildcard_rr = NULL;
|
|
DnsAnswerFlags flags;
|
|
int hashed_size, r;
|
|
bool a, no_closer = false, no_wildcard = false, optout = false;
|
|
|
|
assert(key);
|
|
assert(result);
|
|
|
|
/* First step, find the zone name and the NSEC3 parameters of the zone.
|
|
* it is sufficient to look for the longest common suffix we find with
|
|
* any NSEC3 RR in the response. Any NSEC3 record will do as all NSEC3
|
|
* records from a given zone in a response must use the same
|
|
* parameters. */
|
|
zone = DNS_RESOURCE_KEY_NAME(key);
|
|
for (;;) {
|
|
DNS_ANSWER_FOREACH_FLAGS(suffix_rr, flags, answer) {
|
|
r = nsec3_is_good(suffix_rr, flags, NULL);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
r = dns_name_equal_skip(DNS_RESOURCE_KEY_NAME(suffix_rr->key), 1, zone);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0)
|
|
goto found_zone;
|
|
}
|
|
|
|
/* Strip one label from the front */
|
|
r = dns_name_parent(&zone);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
break;
|
|
}
|
|
|
|
*result = DNSSEC_NSEC_NO_RR;
|
|
return 0;
|
|
|
|
found_zone:
|
|
/* Second step, find the closest encloser NSEC3 RR in 'answer' that matches 'key' */
|
|
p = DNS_RESOURCE_KEY_NAME(key);
|
|
for (;;) {
|
|
_cleanup_free_ char *hashed_domain = NULL;
|
|
|
|
hashed_size = nsec3_hashed_domain(suffix_rr, p, zone, &hashed_domain);
|
|
if (hashed_size == -EOPNOTSUPP) {
|
|
*result = DNSSEC_NSEC_UNSUPPORTED_ALGORITHM;
|
|
return 0;
|
|
}
|
|
if (hashed_size < 0)
|
|
return hashed_size;
|
|
|
|
DNS_ANSWER_FOREACH_FLAGS(enclosure_rr, flags, answer) {
|
|
|
|
r = nsec3_is_good(enclosure_rr, flags, suffix_rr);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
if (enclosure_rr->nsec3.next_hashed_name_size != (size_t) hashed_size)
|
|
continue;
|
|
|
|
r = dns_name_equal(DNS_RESOURCE_KEY_NAME(enclosure_rr->key), hashed_domain);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0) {
|
|
a = flags & DNS_ANSWER_AUTHENTICATED;
|
|
goto found_closest_encloser;
|
|
}
|
|
}
|
|
|
|
/* We didn't find the closest encloser with this name,
|
|
* but let's remember this domain name, it might be
|
|
* the next closer name */
|
|
|
|
pp = p;
|
|
|
|
/* Strip one label from the front */
|
|
r = dns_name_parent(&p);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
break;
|
|
}
|
|
|
|
*result = DNSSEC_NSEC_NO_RR;
|
|
return 0;
|
|
|
|
found_closest_encloser:
|
|
/* We found a closest encloser in 'p'; next closer is 'pp' */
|
|
|
|
/* Ensure this is not a DNAME domain, see RFC5155, section 8.3. */
|
|
if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_DNAME))
|
|
return -EBADMSG;
|
|
|
|
/* Ensure that this data is from the delegated domain
|
|
* (i.e. originates from the "lower" DNS server), and isn't
|
|
* just glue records (i.e. doesn't originate from the "upper"
|
|
* DNS server). */
|
|
if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_NS) &&
|
|
!bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_SOA))
|
|
return -EBADMSG;
|
|
|
|
if (!pp) {
|
|
/* No next closer NSEC3 RR. That means there's a direct NSEC3 RR for our key. */
|
|
if (bitmap_isset(enclosure_rr->nsec3.types, key->type))
|
|
*result = DNSSEC_NSEC_FOUND;
|
|
else if (bitmap_isset(enclosure_rr->nsec3.types, DNS_TYPE_CNAME))
|
|
*result = DNSSEC_NSEC_CNAME;
|
|
else
|
|
*result = DNSSEC_NSEC_NODATA;
|
|
|
|
if (authenticated)
|
|
*authenticated = a;
|
|
if (ttl)
|
|
*ttl = enclosure_rr->ttl;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Prove that there is no next closer and whether or not there is a wildcard domain. */
|
|
|
|
wildcard = strappend("*.", p);
|
|
if (!wildcard)
|
|
return -ENOMEM;
|
|
|
|
r = nsec3_hashed_domain(enclosure_rr, wildcard, zone, &wildcard_domain);
|
|
if (r < 0)
|
|
return r;
|
|
if (r != hashed_size)
|
|
return -EBADMSG;
|
|
|
|
r = nsec3_hashed_domain(enclosure_rr, pp, zone, &next_closer_domain);
|
|
if (r < 0)
|
|
return r;
|
|
if (r != hashed_size)
|
|
return -EBADMSG;
|
|
|
|
DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) {
|
|
_cleanup_free_ char *label = NULL, *next_hashed_domain = NULL;
|
|
|
|
r = nsec3_is_good(rr, flags, suffix_rr);
|
|
if (r < 0)
|
|
return r;
|
|
if (r == 0)
|
|
continue;
|
|
|
|
label = base32hexmem(rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size, false);
|
|
if (!label)
|
|
return -ENOMEM;
|
|
|
|
next_hashed_domain = strjoin(label, ".", zone, NULL);
|
|
if (!next_hashed_domain)
|
|
return -ENOMEM;
|
|
|
|
r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), next_closer_domain, next_hashed_domain);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0) {
|
|
if (rr->nsec3.flags & 1)
|
|
optout = true;
|
|
|
|
a = a && (flags & DNS_ANSWER_AUTHENTICATED);
|
|
|
|
no_closer = true;
|
|
}
|
|
|
|
r = dns_name_equal(DNS_RESOURCE_KEY_NAME(rr->key), wildcard_domain);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0) {
|
|
a = a && (flags & DNS_ANSWER_AUTHENTICATED);
|
|
|
|
wildcard_rr = rr;
|
|
}
|
|
|
|
r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), wildcard_domain, next_hashed_domain);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0) {
|
|
if (rr->nsec3.flags & 1)
|
|
/* This only makes sense if we have a wildcard delegation, which is
|
|
* very unlikely, see RFC 4592, Section 4.2, but we cannot rely on
|
|
* this not happening, so hence cannot simply conclude NXDOMAIN as
|
|
* we would wish */
|
|
optout = true;
|
|
|
|
a = a && (flags & DNS_ANSWER_AUTHENTICATED);
|
|
|
|
no_wildcard = true;
|
|
}
|
|
}
|
|
|
|
if (wildcard_rr && no_wildcard)
|
|
return -EBADMSG;
|
|
|
|
if (!no_closer) {
|
|
*result = DNSSEC_NSEC_NO_RR;
|
|
return 0;
|
|
}
|
|
|
|
if (wildcard_rr) {
|
|
/* A wildcard exists that matches our query. */
|
|
if (optout)
|
|
/* This is not specified in any RFC to the best of my knowledge, but
|
|
* if the next closer enclosure is covered by an opt-out NSEC3 RR
|
|
* it means that we cannot prove that the source of synthesis is
|
|
* correct, as there may be a closer match. */
|
|
*result = DNSSEC_NSEC_OPTOUT;
|
|
else if (bitmap_isset(wildcard_rr->nsec3.types, key->type))
|
|
*result = DNSSEC_NSEC_FOUND;
|
|
else if (bitmap_isset(wildcard_rr->nsec3.types, DNS_TYPE_CNAME))
|
|
*result = DNSSEC_NSEC_CNAME;
|
|
else
|
|
*result = DNSSEC_NSEC_NODATA;
|
|
} else {
|
|
if (optout)
|
|
/* The RFC only specifies that we have to care for optout for NODATA for
|
|
* DS records. However, children of an insecure opt-out delegation should
|
|
* also be considered opt-out, rather than verified NXDOMAIN.
|
|
* Note that we do not require a proof of wildcard non-existence if the
|
|
* next closer domain is covered by an opt-out, as that would not provide
|
|
* any additional information. */
|
|
*result = DNSSEC_NSEC_OPTOUT;
|
|
else if (no_wildcard)
|
|
*result = DNSSEC_NSEC_NXDOMAIN;
|
|
else {
|
|
*result = DNSSEC_NSEC_NO_RR;
|
|
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
if (authenticated)
|
|
*authenticated = a;
|
|
|
|
if (ttl)
|
|
*ttl = enclosure_rr->ttl;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dnssec_test_nsec(DnsAnswer *answer, DnsResourceKey *key, DnssecNsecResult *result, bool *authenticated, uint32_t *ttl) {
|
|
DnsResourceRecord *rr;
|
|
bool have_nsec3 = false;
|
|
DnsAnswerFlags flags;
|
|
int r;
|
|
|
|
assert(key);
|
|
assert(result);
|
|
|
|
/* Look for any NSEC/NSEC3 RRs that say something about the specified key. */
|
|
|
|
DNS_ANSWER_FOREACH_FLAGS(rr, flags, answer) {
|
|
|
|
if (rr->key->class != key->class)
|
|
continue;
|
|
|
|
switch (rr->key->type) {
|
|
|
|
case DNS_TYPE_NSEC:
|
|
|
|
r = dns_name_equal(DNS_RESOURCE_KEY_NAME(rr->key), DNS_RESOURCE_KEY_NAME(key));
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0) {
|
|
if (bitmap_isset(rr->nsec.types, key->type))
|
|
*result = DNSSEC_NSEC_FOUND;
|
|
else if (bitmap_isset(rr->nsec.types, DNS_TYPE_CNAME))
|
|
*result = DNSSEC_NSEC_CNAME;
|
|
else
|
|
*result = DNSSEC_NSEC_NODATA;
|
|
|
|
if (authenticated)
|
|
*authenticated = flags & DNS_ANSWER_AUTHENTICATED;
|
|
if (ttl)
|
|
*ttl = rr->ttl;
|
|
|
|
return 0;
|
|
}
|
|
|
|
r = dns_name_between(DNS_RESOURCE_KEY_NAME(rr->key), DNS_RESOURCE_KEY_NAME(key), rr->nsec.next_domain_name);
|
|
if (r < 0)
|
|
return r;
|
|
if (r > 0) {
|
|
*result = DNSSEC_NSEC_NXDOMAIN;
|
|
|
|
if (authenticated)
|
|
*authenticated = flags & DNS_ANSWER_AUTHENTICATED;
|
|
if (ttl)
|
|
*ttl = rr->ttl;
|
|
|
|
return 0;
|
|
}
|
|
break;
|
|
|
|
case DNS_TYPE_NSEC3:
|
|
have_nsec3 = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* OK, this was not sufficient. Let's see if NSEC3 can help. */
|
|
if (have_nsec3)
|
|
return dnssec_test_nsec3(answer, key, result, authenticated, ttl);
|
|
|
|
/* No approproate NSEC RR found, report this. */
|
|
*result = DNSSEC_NSEC_NO_RR;
|
|
return 0;
|
|
}
|
|
|
|
static const char* const dnssec_result_table[_DNSSEC_RESULT_MAX] = {
|
|
[DNSSEC_VALIDATED] = "validated",
|
|
[DNSSEC_INVALID] = "invalid",
|
|
[DNSSEC_SIGNATURE_EXPIRED] = "signature-expired",
|
|
[DNSSEC_UNSUPPORTED_ALGORITHM] = "unsupported-algorithm",
|
|
[DNSSEC_NO_SIGNATURE] = "no-signature",
|
|
[DNSSEC_MISSING_KEY] = "missing-key",
|
|
[DNSSEC_UNSIGNED] = "unsigned",
|
|
[DNSSEC_FAILED_AUXILIARY] = "failed-auxiliary",
|
|
[DNSSEC_NSEC_MISMATCH] = "nsec-mismatch",
|
|
[DNSSEC_INCOMPATIBLE_SERVER] = "incompatible-server",
|
|
};
|
|
DEFINE_STRING_TABLE_LOOKUP(dnssec_result, DnssecResult);
|